Gallium nitride high-electron-mobility transistors (GaN HEMTs) are at a point of rapid growth in defense (radar, SATCOM) and commercial (5G and beyond) industries. This growth also comes at a point at which the standard GaN heterostructures remain unoptimized for maximum performance. For this reason, the shift to the aluminum nitride (AlN) platform is disclosed. AlN allows for smarter, highly-scaled heterostructure design that improves the output power and thermal management of GaN amplifiers. Beyond improvements over the incumbent amplifier technology, AlN allows for a level of integration previously unachievable with GaN electronics. State-of-the-art high-current p-channel FETs, mature filter technology, and advanced waveguides, all monolithically integrated with an AlN/GaN/AlN HEMT, is made possible with aluminum nitride. It is on this AlN platform that nitride electronics may maximize their full high-power, highspeed potential for mm-wave communication and high-power logic applications.

Gallium nitride high-electron-mobility transistors (GaN HEMTs) are at a point of rapid growth in defense (radar, SATCOM) and commercial (5G and beyond) industries. This growth also comes at a point at which the standard GaN heterostructures remain unoptimized for maximum performance. For this reason, the shift to the aluminum nitride (AlN) platform is disclosed. AlN allows for smarter, highly-scaled heterostructure design that improves the output power and thermal management of GaN amplifiers. Beyond improvements over the incumbent amplifier technology, AlN allows for a level of integration previously unachievable with GaN electronics. State-of-the-art high-current p-channel FETs, mature filter technology, and advanced waveguides, all monolithically integrated with an AlN/GaN/AlN HEMT, is made possible with aluminum nitride. It is on this AlN platform that nitride electronics may maximize their full high-power, highspeed potential for mm-wave communication and high-power logic applications.

The non-linear behavior of power amplifier is linearized using a pre-distorter that is adaptive to changes in the behavior of the power amplifier and uses an artificial neural network. According to embodiments presented here, the pre-distorter's artificial neural network is model-trained from time to time to learn the inverse of the transfer function of the power amplifier by using a second pre-distorter modeling system. The second modeling system determines the parameters of the inverse of the transfer function of the power amplifier using a least square method by using the (un-distorted) output signal samples of the power amplifier. Using the output of the second system as output to train the neural network enables the neural network to more successfully linearize the power amplifier's behavior. Furthermore, the trained artificial neural network as the pre-distorter can be implemented in hardware and presents a small form factor.

According to certain aspects, a chip includes a pad, a power amplifier, a transformer coupled between an output of the power amplifier and the pad, a transistor coupled between the transformer and a ground, and a first clamp circuit coupled between a gate of the transistor and a drain of the transistor.

According to certain aspects, a chip includes a pad, a power amplifier, a transformer coupled between an output of the power amplifier and the pad, a transistor coupled between the transformer and a ground, and a first clamp circuit coupled between a gate of the transistor and a drain of the transistor.

A power amplifier circuit includes an amplifier transistor which amplifies a radio frequency signal applied to its base and outputs the amplified signal; a resistance element having a first end, and a second end electrically connected to the base of the amplifier transistor; a first bias transistor having a collector to which a first voltage is applied, a base to which a first bias voltage is applied, and an emitter electrically connected to the first end of the resistance element and which supplies a bias current to the base of the amplifier transistor through the resistance element; and a second bias transistor having an emitter electrically connected to the emitter of the first bias transistor and the first end of the resistance element, a base to which a second bias voltage is applied, and a collector to which a second voltage lower than the first voltage is applied.

A power amplifier circuit includes an amplifier transistor which amplifies a radio frequency signal applied to its base and outputs the amplified signal; a resistance element having a first end, and a second end electrically connected to the base of the amplifier transistor; a first bias transistor having a collector to which a first voltage is applied, a base to which a first bias voltage is applied, and an emitter electrically connected to the first end of the resistance element and which supplies a bias current to the base of the amplifier transistor through the resistance element; and a second bias transistor having an emitter electrically connected to the emitter of the first bias transistor and the first end of the resistance element, a base to which a second bias voltage is applied, and a collector to which a second voltage lower than the first voltage is applied.

A semiconductor device includes first member that includes a switch made of a semiconductor element made from an elemental semiconductor. The first member is joined to a second member including a radio-frequency circuit including a semiconductor element made from a compound semiconductor. The switch and the radio-frequency circuit are connected by a path. The path includes an inter-member connection wire made of a metal pattern arranged on an interlayer insulating film extending from a surface of the second member to a surface of the first member or a conductive member allowing a current to flow in a direction crossing an interface where the first member and the second member are joined.

A semiconductor device including a radio-frequency amplifier circuit and a band selection switch is mounted on or in a module substrate. An output matching circuit coupled between the radio-frequency amplifier circuit and the band selection switch is on or in the module substrate. The semiconductor device includes a first member at which the band selection switch having a semiconductor element made of an elemental semiconductor is formed and a second member joined to the first member in surface contact therewith. The radio-frequency amplifier circuit including a semiconductor element made of a compound semiconductor is formed at the second member. Conductive protrusions are raised from first and second members. The semiconductor device is mounted on or in the module substrate with the conductive protrusions interposed therebetween, and in plan view, is in close proximity to the output matching circuit or overlaps a passive element constituting the output matching circuit.

A semiconductor device including a radio-frequency amplifier circuit and a band selection switch is mounted on or in a module substrate. An output matching circuit coupled between the radio-frequency amplifier circuit and the band selection switch is on or in the module substrate. The semiconductor device includes a first member at which the band selection switch having a semiconductor element made of an elemental semiconductor is formed and a second member joined to the first member in surface contact therewith. The radio-frequency amplifier circuit including a semiconductor element made of a compound semiconductor is formed at the second member. Conductive protrusions are raised from first and second members. The semiconductor device is mounted on or in the module substrate with the conductive protrusions interposed therebetween, and in plan view, is in close proximity to the output matching circuit or overlaps a passive element constituting the output matching circuit.